Response of bt cotton to early season floral bud removal: Growth and Yield Distribution

Abstract

Response of Bt cotton to square removal was studied to determine the impact of loss of fruiting forms due to insect pest attack or physiological damage on phenology, growth and yield of cotton at Punjab Agricultural University, Ludhiana, India. Three Bt cotton hybrids were assessed for the removal of floral buds for consecutive four weeks @ 25% and 50% from the day squares start initiation. The vegetative growth (plant height) in 25% and 50% square removal treatments increased significantly (˂0.0001) over that of undamaged control treatment among all the hybrids. In contrast, the reproductive growth (number of squares, flowers, bolls per plant and seed cotton yield) significantly decreased in 50% simulation treatments over that of undamaged control treatment and 25% square removal treatment in different hybrids. The decrease in seed cotton yield was 8.6 and 10.4% as compared to 0 and 25% square removal treatments, respectively. The results indicate that Bt cotton can tolerate at least modest levels (25%) of square removal without yield reduction.